For the past few decades, the freight hauling industry has relied on a tractor/trailer combination for hauling cargo over long distances. These combinations consist of a tractor that is mechanically coupled to a trailer so it can pull the trailer and its cargo. Because the trailer typically has no power source or control mechanisms, it is necessary to supply power and communicate control signals via a subsystem link from the tractor to the trailer for the proper functioning of the tractor/trailer combination. Since a tractor is not permanently linked to a specific trailer, it is desirable that this subsystem link comply with relevant industry standards in order for a tractor to be compatible with different trailers.
Electrical power exchange between a tractor and trailer is currently accomplished via a seven wire cable and an associated seven pin connector. This electrical connection system, capable of carrying seven separate circuits, provides electrical power for various trailer lighting functions such as turn signals, brake lamps, tail lamps, side marker lamps, clearance lamps and dome lamps, as well as a ground reference for these electrical circuits. In an effort to provide uniformity throughout the industry, the Society of Automotive Engineers (SAE) has promulgated standards for both the seven wire cable (SAE-J1067) and the associated seven pin connectors (SAE-J560b).
As used hereinafter, the term “tractor” refers to any vehicle having another vehicle in tow, and therefore includes medium or heavy duty trucks, tractor trucks and tractor truck/trailer combinations having a further vehicle or vehicles in tow. The term “trailer” as used hereinafter refers to any vehicle towed by another vehicle, and therefore includes semi-trailers, and the like.
Referring to FIG. 1, a diagram of a typical prior art electrical connection system 50 for routing electrical power to an electrical trailer system is shown. A tractor 52 includes a tractor power system 54 which acts as a power source to provide electrical power to a tractor electrical system 56 when the tractor 52 is in operation. Connected to tractor electrical system 56 are seven electrical lines 581, 582, . . . 587, which are configured in accordance with SAE-J1067 standards. Electrical lines 581, 582, . . . 587 extend from tractor electrical system 56 into a connector housing 60, commonly referred to as a “tractor nosebox”, which is typically attached to an exterior surface of tractor 52. Housing 60 has a seven conductor electrical connector 62 associated therewith, and electrical lines 581, 582, . . . 587 are connected thereto in accordance with SAE-J560b standards.
A trailer 64 includes a trailer electrical system 66 which is operable to provide the aforementioned trailer functions. Connected to trailer electrical system 66 are seven electrical lines 681, 682, . . . 687 which are configured in accordance with SAE J-1067 standards. Electrical lines 681, 682, . . . 687 extend from trailer electrical system 66 into a connector housing 70, or “trailer nosebox”, which is typically attached to an exterior surface of trailer 64. Housing 70 has a seven conductor electrical connector 72 associated therewith, to which electrical lines 681, 682, . . . 687 are connected in accordance with SAE-J560b standards.
A seven conductor connector/cable 74, or “power cord”, connects tractor electrical connector 62 to trailer electrical connector 72 so that the tractor electrical system 56 controls, and provides electrical power to, the trailer electrical system 66.
Referring now to FIG. 2, a typical power cord 74 is shown. Power cord 74 includes an SAE-J1067 seven wire jacketed cable 76 with an SAE-J560b seven conductor plug connector 78 connected thereto at each end. Each plug connector 78 has a front face 82 and a socket guide 80 extending away from the front face 82. FIG. 3 shows the front face 82 of plug connector 78 which defines seven receptacles, or electrical terminals 84-96, therein, each of which forms an electrical connection with one of the seven wires contained within cable 76. The sizing and color standard of the seven circuit wires are set forth in SAE-J1067.
Referring now to FIG. 4, an example of a typical electrical connection between connector housing 60 (or 70), attached to tractor 52 (or trailer 64), and power cord 74 is shown. Connector housing 60 (70) typically includes a socket cover 116 connected to housing 60 (70) by hinged connection 118, which is biased, such that cover 116 provides an environmentally and mechanically protecting seal over socket 114 when not in use. Socket 114 has been generally referred as electrical connector 62 (or 72) (FIG. 1.) Socket 114 is configured complementary to plug 78 of power cord 74, and includes a socket guide slot 112 (FIG. 5) such that plug 78 may be received within socket 114, having socket guide 80 align with socket guide slot 112 when cover 116 is lifted to expose socket 114. Cover 116 also typically includes a projection 120 which operates to engage socket guide 80 of plug 78, which, under the normal bias of cover 116 provided by hinged connection 118, acts to retain plug 78 within socket 114, thereby maintaining electrical connection therebetween.
FIG. 5 shows a cross-section, taken along section lines 5-5 of FIG. 4, of the electrical connection between plug 78 and socket 114. Socket 114 includes seven “pins” or electrical terminals 122-134, which are typically configured in accordance with SAE-J560b standards, and which are received within corresponding receptacle terminals 84-96 of plug 78. The specifics of the sizing and geometry standards of SAE-J1067 cable and SAE-J560b plugs and sockets are set forth in “Seven Truck-Trailer Jumper-Cable,” of the 2000 SAE Handbook. Generally, for a SAE-J560b socket, the seven pins are positioned in a standard pattern such that a central pin surrounded by six pins spaced equiangularly from each other and from the center pin. Per the SAE-J560b standard, the pin located at the 12 o'clock position, in reference to the socket guide slot 112, is slightly larger in diameter than the other six standard pins. Traditionally, the pins are referred to by the color and/or function of the circuit wire to which the pins are ultimately connected, i.e. pin 122 at the 12 o'clock position is white for the main ground circuit, pin 128 at the 6 o'clock position is for the red circuit, pins 124, 126, 130, 132, 134 are black, yellow, blue, green, and brown, respectively.
Recently, technological advances in the tractor/trailer industry have created a need to provide tractors and trailers with additional electrical functions. Examples of such functions include anti-lock brakes, lift gates, and electronic suspension control, as well as diagnostic control and fault detection of various trailer functions. Furthermore, there is a desire within the industry to have the capability of providing for a parallel main harness when a double trailer hook-up is required.
The prior art interface system as described in FIG. 1 does not have the capacity to provide for the extra functions. A recent government ruling further aggravates the problem by dedicating the blue circuit to the trailer anti-lock brake system (ABS). Although provisions for additional power cables and connectors may be a viable solution in the short term, this approach is generally a costly solution since that tends to limit compatibility between tractors and trailers. Additionally, it is still generally considered desirable by owners and operators of tractor/trailer combinations to maintain the use of the universal J560b plugs, sockets and the associated J1067 power cords. However, before the universal J560/J1067 hardware standard is to be used to provide electrical interface for the added communication and power needs, two issues must be addressed. First, the system must provide the capability of loading multiple functions on one circuit. Secondly, the system must provide connection points for the added functions.
An example of a design utilizing the SAE-J1067/J560b electrical interface system to provide a connector assembly with extra terminal receptacles to provide additional connection points to the electrical circuits bridging the tractor/trailer combination is set forth in U.S. Pat. No. 6,558,167, which is assigned to the same assignee as the present invention. While this innovative circuit design may have addressed the issue of providing extra terminal receptacles allowing the added functions to connect to the circuits, there is a need for a system which provides for ease of installation, repair and/or replacement of an interchangeable connector assembly with little disruption to the electrical connections made with the extra terminal receptacles.
What is therefore needed are assemblies which are compatible with existing SAE-J1067/J506b power cords and plugs but which also permit new electrically controlled tractor/trailer functions and features to be connected to the existing circuits without additional electrical connection hardware or splicing, with certain components being easily removable, with little disruption to other components, providing the flexibility of changing a configuration or replacing a damaged unit. The present disclosure is directed toward devices and methods which meet these needs.